Q&A: Rotting Potatoes Question: Many of our potatoes have rotten spots that spread, eventually turning the whole potato into a soft pulpy rot. What is causing this and what can we do to prevent it from happening next year?
Answer: If your potato plants appeared healthy all season, then the symptoms you describe can those of bacterial soft rot, caused by a bacteria called Erwinia. It's difficult to tell which of the remaining tubers might be infected because the bacteria can enter through wounds, injuries or even through natural openings (lenticels) in the skin. Check each potato for injuries or wounds and discard those that seem suspect. Also, potatoes that have suffered from late blight (the infamous Irish Potato Famine blight) often turn to slime, too. If the entire plants blackened and died before their time, blight is probably the culprit. There are several potato varieties that show resistance to late blight; Elba is currently the most resistant potato variety available. Potato varieties with moderate levels of resistance include Kennebec, Sebago, Allegany, and Rosa. To reduce problems with disease, buy only potatoes that are certified disease-free; don't save potato seed from year to year. Examine your seed potatoes carefully before you plant, and plant only sound, blemish-free tubers. Rotate crops in the potato family (which includes tomatoes, peppers, and eggplant) on a 4-year cycle in your garden plot. Pull up spent plants and clean up garden debris in the fall and do not compost diseased plant material. |
Q&A: Encouraging Poinsettia to Bloom Question: I've kept my poinsettia growing all summer. How do I get it to bloom again in time for the holidays?
Answer: Poinsettias are induced into blooming by shorter daylength. In late September begin placing the plant in total darkness for 13 to 14 hours every night. The spot must be really dark--no streetlights shining in, no occasional visitors turning the lights on. A dark, unused closet is a good spot. Each morning, bring the plant out and place it in bright light for the remaining 10 or 11 hours, placing it back in the closet each evening. This will give them the short days they need to trigger the response to color up in time for the holidays.
Keep and eye on the plant, and when the bracts have started showing color again--usually about 4 weeks--you can stop the nightly ritual and treat them like any other houseplant. Place then in a bright spot and keep soil evenly moist but not soggy. |
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